Bicycles, and more specifically pedal-assist bicycles, with an electric motor that assists the movement of the bicycle only when the rider is pedaling are currently well known. The power used to drive said electric motor is supplied by an electric battery.
These bicycles generally also comprise a hinge system on the diagonal or main tube of the frame allowing to fold the rear part of the bicycle sideways onto the front part thereof.
There are several models of pedal-assist bicycles in the market where the battery is located on the diagonal tube of the bicycle frame, such as in Utility Model ES1072110U, held by the author of the present invention, such that it is difficult if not impossible to install an articulated joint or hinge in the diagonal tube due to the presence of the battery.
Thus, to provide a folding capability to pedal-assist bicycles in which the battery is placed on the diagonal tube of the frame, folding systems have been conceived such as that described in international patent application WO0302267A1, which allows folding sideways the rear part of the bicycle onto the front part using a hinge fitted in the union of the diagonal tube to the seat tube. However, the drawback of the folding system is that the hinge is located at a point where many loads or strains coincide when the bicycle is being used, affecting the sturdiness of the system and making it prone to breaks and/or malfunctions, mainly due to clearances, friction and excessive wear of the components, substantially reducing the lifetime thereof.
In addition, application EP2581298A1, also by the holder, describes a folding bicycle that allows combining the inclusion of an electric battery on the diagonal tube of the frame and a folding system that reduces the loads applied at the weak points of the bicycle, such as the union points between the seat tube and the diagonal tube; however, this has the drawback of requiring removing the front wheel from its fork, thereby increasing the time, complexity and effort required in the folding process.